Android自定义View实现验证码

本来是想学习一下张鸿样的自定义View的，但是看了以后，觉得楼主这篇还不错，就拿来改了改，改成了验证码，希望对你们有帮助！

先来看看自定义View的一般步骤：

1. 先把自己需要的属性在(attrs.xml)进行定义，比如

 <declare-styleable name="MTextView_One">        <attr name="titleText" format="string" />        <attr name="titleTextViewColor" format="color" />        <attr name="titleTextSize" format="dimension" />    </declare-styleable>

1. 然后自定义名字继承View
2. 获取自定义的熟悉
3. 重写onMeasure方法

4. 重写onDraw方法

   来一个效果图(不会做动态图，将就看)

   

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源码下载（项目是在AndroidStudio环境下运行的噢）

点击这里下载源码
/**
* Created by wangjilei on 2015/11/24.
* 功能：自定义View实现验证码
*/
public class MTextView_One extends View {

private String mTitleText;//文本private int mTitleTextColor;//文本的颜色private int mTitleTextSize;//文本的大小private Rect mBound;//绘制时控制文本绘制的范围private Paint mPaint;//画笔private int width = 0;private int height = 0;public static final int POINT_NUM = 100;//点数设置(用于添加噪点)public static final int LINE_NUM = 10;//线条数public MTextView_One(Context context, AttributeSet attrs) {    this(context, attrs, 0);}public MTextView_One(Context context) {    this(context, null);}/** * 获得我自定义的样式属性 * * @param context * @param attrs * @param defStyle */public MTextView_One(Context context, AttributeSet attrs, int defStyle) {    super(context, attrs, defStyle);    /**     * 获得我们所定义的自定义样式属性     */    TypedArray a = context.getTheme().obtainStyledAttributes(attrs, R.styleable.MTextView_One, defStyle, 0);    int n = a.getIndexCount();    for (int i = 0; i < n; i++) {        int attr = a.getIndex(i);        switch (attr) {            case R.styleable.MTextView_One_titleText:                mTitleText = a.getString(attr);                break;            case R.styleable.MTextView_One_titleTextViewColor:                // 默认颜色设置为黑色                mTitleTextColor = a.getColor(attr, Color.BLUE);                break;            case R.styleable.MTextView_One_titleTextSize:                // 默认设置为16sp，TypeValue也可以把sp转化为px                mTitleTextSize = a.getDimensionPixelSize(attr, (int) TypedValue.applyDimension(                        TypedValue.COMPLEX_UNIT_SP, 16, getResources().getDisplayMetrics()));                break;        }    }    a.recycle();    init();}private void init() {    /**     * 获得绘制文本的宽和高     */    mPaint = new Paint();    mPaint.setTextSize(mTitleTextSize);    // mPaint.setColor(mTitleTextColor);    mBound = new Rect();    mPaint.getTextBounds(mTitleText, 0, mTitleText.length(), mBound);    /**     *点击自动改变数字     */    this.setOnClickListener(new OnClickListener() {        @Override        public void onClick(View v) {            mTitleText = CheckGetUtil.randomText();            postInvalidate();            Intent intent = new Intent();            intent.putExtra("code", mTitleText);        }    });}@Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {    super.onMeasure(widthMeasureSpec, heightMeasureSpec);    /**     * 设置宽度     */    int specMode = MeasureSpec.getMode(widthMeasureSpec);    int specSize = MeasureSpec.getSize(widthMeasureSpec);    switch (specMode) {        case MeasureSpec.EXACTLY:// 明确指定了            width = getPaddingLeft() + getPaddingRight() + specSize;            break;        case MeasureSpec.AT_MOST:// 一般为WARP_CONTENT            width = getPaddingLeft() + getPaddingRight() + mBound.width();            break;    }    /**     * 设置高度     */    specMode = MeasureSpec.getMode(heightMeasureSpec);    specSize = MeasureSpec.getSize(heightMeasureSpec);    switch (specMode) {        case MeasureSpec.EXACTLY:// 明确指定了            height = getPaddingTop() + getPaddingBottom() + specSize;            break;        case MeasureSpec.AT_MOST:// 一般为WARP_CONTENT            height = getPaddingTop() + getPaddingBottom() + mBound.height();            break;    }    setMeasuredDimension(width, height);}@Overrideprotected void onDraw(Canvas canvas) {    //绘制背景    mPaint.setColor(Color.YELLOW);    canvas.drawRect(0, 0, getMeasuredWidth(), getMeasuredHeight(), mPaint);    //绘制数字    mPaint.setColor(mTitleTextColor);    canvas.drawText(mTitleText, getWidth() / 2 - mBound.width() / 2, getHeight() / 2 + mBound.height() / 2, mPaint);    //绘制圆形噪点    int[] point;    mPaint.setColor(Color.RED);    for (int i = 0; i < POINT_NUM; i++) {        point = CheckGetUtil.getPoint(height, width);        canvas.drawCircle(point[0], point[1], 2, mPaint);    }    //绘制直线    mPaint.setColor(Color.BLUE);    int[] line;    for (int i = 0; i < LINE_NUM; i++) {        line = CheckGetUtil.getLine(height, width);        canvas.drawLine(line[0], line[1], line[2], line[3], mPaint);    }}

}